JPS5851416Y2 - Venting device for the ignition interrupter chamber in internal combustion engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ventilation device for an ignition interrupter chamber in an internal combustion engine.

In general, the ignition interrupter chamber is designed to allow ventilation by communicating with the atmosphere in order to prevent the internal interrupter from becoming damp and causing electrical failures, but dust and dirt can escape from the ventilation path. If they enter, there is a risk that the contact points of the interrupter may cause poor contact or accelerate the wear of the sliding parts.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a ventilation device that can effectively prevent dust from entering the east ignition interrupter chamber, has a simple structure, is easy to manufacture, and can be provided at low cost.

An embodiment of the present invention will be described below with reference to the drawings. Reference numeral 1 denotes an engine body that supports a crankshaft 2 via a bearing 3 and an oil seal 4. The outer surface of the engine body is raised in a certain area around the crankshaft 2. Interrupter mounting base 5
is formed, and an outer peripheral flange portion 6a of the cover 6 is formed on the peripheral edge thereof.
are joined together via a gasket 7 to define an ignition interrupter chamber 8 on the mounting base 5, in which an ignition interrupter 9 is installed, and the flange portion 6a is removably attached to the mounting base 5 using screws 1G and 10. Fixed.

The ignition interrupter 9 has a board 12 with a fixed contact 11 attached to one end.
and an oscillator 14 which is supported by a pivot 13 on a base plate 12 and has a movable contact 11' at one end. The child 14 is a cam 1 formed integrally with the crankshaft 2.
When the oscillator 14 is held in the engaged position with the cam 16 and is oscillated by the rotation of the cam 16, an ignition coil (not shown) can be operated by opening and closing the contacts 11 and 11'.

An eaves portion 6b surrounding the outer periphery of the mounting base 5 is provided on the outer periphery of the flange portion 6a of the cover 6, and an elongated U-shaped groove 17 is recessed in the joint surface of the mounting base 5 with the cover 6.

This U-shaped groove 17 is opened at one end into the ignition interrupter chamber 8 and at the other end at the outer circumferential surface of the mounting base 5, so that the ignition interrupter chamber 8 is always communicated with the atmosphere. They are spaced apart from each other in the circumferential direction of the joint surface.

The external force open end of the U-shaped groove 17, that is, the open end on the outer peripheral surface side of the mounting base 5, is always covered by the eaves 6b of the cover 6 through a gap that communicates with the outside. In addition, the U-shaped groove 17 extends long and narrow in the circumferential direction of the joint surface between the cover 6 and the mounting base 5, and is curved in the middle, so that the flow path resistance is large. It is possible to sufficiently attenuate the kinetic energy of the passing outside air and efficiently separate the dust contained therein.

Further, since the U-shaped groove IT is long, the passage area can be increased while ensuring a predetermined flow path resistance, and clogging of the U-shaped groove 17 due to dust or the like can be prevented.

In the figure, 18 is a seal member fitted into a through hole penetrated by the crankshaft 2 of the cover 6, and 19 is a part of an engine cooling fan that also serves as a flywheel of the crankshaft 2.

As described above, according to the present invention, on the peripheral edge of the interrupter mounting base 5 formed protrudingly on one side of the engine main body 1, a plate-shaped plate defining the ignition interrupter chamber 8 between the interrupter mounting base 5 and the ignition interrupter mounting base 5 is provided. A cover 6 is removably fixed, an elongated U-shaped groove 1T is recessed in the joint surface of the mounting base 5 with the cover 6, and one end of this U-shaped groove 17 is connected to the ignition interrupter chamber 8, and The other ends of the U-shaped groove 17 are opened on the outer peripheral surface of the mounting base 5, and the open ends are spaced apart from each other in the circumferential direction of the joint surface. Since the eaves portion 6b covering the open end on the outer circumferential surface side is connected to the outside through a gap communicating with the outside, the U-shaped groove 17 enables ventilation of the ignition interrupter chamber 8, and the internal interrupter 9 can be prevented from becoming damp.

In particular, by covering the external force opening end of the U-shaped groove 17, that is, the opening end on the outer peripheral surface side of the mounting base 5, with the eaves 16b of the cover 6 through a gap that communicates with the outside, it is possible to enter the U-shaped groove IT from the outside. In addition, by separating both open ends of the U-shaped groove 1T from each other in the circumferential direction of the joint surface of the cover 6 and the mounting base 5, the U-shaped The groove IT can be extended in the circumferential direction regardless of the width of the joint surface in the radial direction, and the middle of the ridge groove 17 can be inevitably curved, making the flow path resistance relatively large. It is possible to attenuate the kinetic energy of the outside air passing through it and efficiently separate the dust contained therein, and as a result, the infiltration of dust into the ignition interrupter chamber 8 is extremely effectively prevented. Therefore, failure of the interrupter 9 due to dust can be prevented.

Furthermore, since the U-shaped groove 17 is long, the passage area can be increased while ensuring a predetermined flow path resistance, and clogging of the U-shaped groove 17 due to dust or the like can be prevented.

The ventilation device of the present invention can be constructed by simply joining a single plate cover 6 to the mounting base 5 that is integrated with the engine body 1, so the number of parts is small, the structure is simple, and costs are reduced. Moreover, cleaning is easy because the U-shaped groove 17 can be widely opened to the outside by simply separating the cover 6 from the mounting base 5.

Furthermore, the U-shaped groove 17, which is relatively troublesome to mold, can be easily molded at the same time as the casting of the mounting base 5, that is, the casting of the engine body 1, and the eaves portion 6b can be formed simultaneously with the press molding of the cover 6. Because it can be easily molded at the same time,
Overall, manufacturing is extremely easy and costs can be further reduced.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of an internal combustion engine equipped with an embodiment of the device of the present invention, and FIG. 2 is a sectional view taken along the line Tl--Tl in FIG. 1... Engine body, 5... Mounting stand, 6... Cover,
6b...Eave part, 8...Ignition interrupter chamber, 17...U
Groove.

Claims (1)

[Scope of utility model registration request] A plate-shaped cover 6 defining an ignition interrupter chamber 8 between the mount 5 and the ignition interrupter mount 5 is removably fixed to the peripheral edge of the interrupter mount 5 formed protrudingly on one side of the engine body 1. An elongated U-shaped groove 17 is formed in the joint surface of the mounting base 5 with the cover 6, and one end of this U-shaped groove 17 is connected to the ignition interrupter 8, and the other end is connected to the outer peripheral surface of the mounting base 5. The opening ends of the U-shaped groove IT on the outer peripheral surface side of the mounting base 5 are connected to the outside on the outer periphery of the cover 6. A ventilation device for an ignition interrupter chamber in an internal combustion engine, which is formed by integrally connecting eaves portions 6b which are covered through a communicating gap.